• New Contest Starting Now! This Target Haunts Me

    Tell us about the one that got away, the flier that ruined your group, the zero that drifted, the shot you still see when you close your eyes. Winner will receive a free scope!

    Join contest

Using Tape on the back of a loaded round to check or set headspace. . . .

Terry Cross

Terry Cross

Dingleberry
Supporter
Commercial Supporter
Full Member
Minuteman
Mar 15, 2003
3,369
13,790
Alexandria, LA 71303
www.kmwlrs.com
#1
When proper Headspace gauges are not available, this is a pretty widely used method of spitballing a sorta-close headspace. It has been used for a long time and is considered a rough cheat code to make sure the HS is in the right zip code.

My concern recently is that we have been seeing ammo quality (consistency specifically ) being all over the place. Seemingly in the last 20yrs it has gotten worse instead of better. Maybe because of 2 or 3 back to back ME wars and the producers not taking time to PM their machines and double check QC processes as much. (?)

Anyway . . . . . . . my point is that I have a literal pile of factory ammo that won't go into correctly headspaced factory chambers.

The worst offender is Hornady but I have a few Federal, Win and even Sig.
These rounds look perfect visually but are too long on the shoulder datum -> headstamp dimension. We have also seen a few that are too short on the opposite of that dimensional spectrum to the point they are inducing ignition problems.

I don't think using such a round with tape on the rear to "set" or check headspace would be "dangerous" but if the sample cartridge was out of spec, it could cause excessive brass stretch.
It could even cause the phone to ring at shops like Wade's to bitch about an out of spec chamber that is actually in spec.

@spife7980 I'm not arguing or trying to bust your chops. Just sharing my personal thoughts based on personal concerns and experience, neither of which proves I'm right. So this post is simply meant as food for thought and a "rumble strip" warning to proceed cautiously for the novices.
 
  • Like
  • Haha
Reactions: RTH1800, MarinePMI, anon and 8 others
#3
ShtrRdy said:
Which cartridge names are you seeing the most? I'm wondering if they are ones that had a disconnect between the SAAMI cartridge drawing and chamber drawing.
Click to expand...
.308s mostly. This is obviously due to the lane I work in both building and teaching. However I also have samples of 6.5CM, 6ARC and 300BlkOut with same issue.
 
  • Like
Reactions: TheBigCountry
#5
+1. One question for clarification. Are you seeing whole cases/lots of ammo out of spec (as described). Or are you seeing something more along the lines of a couple rounds per box being off, or a couple of boxes per case affected, etc.
 
#6
I’ve done this many times using yellow credit card receipt instead of tape. It’s always worked great.

It’s disappointing to learn that factory ammo is coming out too long. Normally, it’s at min to give the best chance of working in pretty much any chamber it might find its way into.
 
#8
AR-180 said:
It’s disappointing to learn that factory ammo is coming out too long.
Click to expand...
.....and sometimes too short.
.....and sometimes with split necks.
.....and sometimes with backwards primers

AR-180 said:
Normally, it’s at min to give the best chance of working in pretty much any chamber it might find its way into.
Click to expand...
That is supposed to be the standard.
Largest SAAMI cartridge would still fit in the smallest SAAMI chamber for any given factory OEM stamp.
Smallest SAAMI cartridge would still fit and fire in the largest SAAMI chamber for any given factory OEM stamp.

Obviously this is not reality though.

1753886390816.png
 
  • Like
Reactions: flogxal, FJS, AR-180 and 1 other person
#10
ma smith said:
+1. One question for clarification. Are you seeing whole cases/lots of ammo out of spec (as described). Or are you seeing something more along the lines of a couple rounds per box being off, or a couple of boxes per case affected, etc.
Click to expand...
Both.

A few years ago, we saw a whole skid that had maybe 20% oversize.
But by far the majority of the instances are only 1 or 2 per class. Some classes have zero issues.
Then again, 1 or 2 per class is too many in my opinion.
 
Last edited:
  • Like
Reactions: flogxal, MarinePMI, DIBBS and 1 other person
#11
Fig said:
What's the fix? Check every round with a headspace gage? With the guys you train that may be the only prudent option. Not the same when you are shooting "work guns" that have to work every time.
Click to expand...
My soap box preaching about the shooter being the last line in the QC process is due to seeing so much of this.

I highly recommend that every shooter does goes through an ammo checklist for each and every round they have bagged to deploy with. Most are only 20 to 40 rounds.

Visually inspect each round.
Check for split necks
Check for primer / primer orientation
Check headstamp to confirm it is what was supposed to be in the box.*
Check edge of the neck to confirm it is free of shaved jacket material.

Cycle every round through the rifle that it is to deploy with. If the bolt hesitates to go down or exhibits signs of a "snug" fit, that round should be segregated from the rest and not included in the deployable loadout.

The screened ammo stays with the kit for at least 6 months and then is rotated out during practice/training and replaced with newly screened ammo.

*We have seen and/or heard of 243 Win and 7-08 rounds being found in boxes of .308.

Because it is so important, I literally have this POI in every class regardless of what level instruction the class is destined for.
 
  • Like
  • Love
Reactions: flogxal, mark5pt56, MarinePMI and 6 others
#14
Terry Cross said:
My soap box preaching about the shooter being the last line in the QC process is due to seeing so much of this.

I highly recommend that every shooter does goes through an ammo checklist for each and every round they have bagged to deploy with. Most are only 20 to 40 rounds.

Visually inspect each round.
Check for split necks
Check for primer / primer orientation
Check headstamp to confirm it is what was supposed to be in the box.*
Check edge of the neck to confirm it is free of shaved jacket material.

Cycle every round through the rifle that it is to deploy with. If the bolt hesitates to go down or exhibits signs of a "snug" fit, that round should be segregated from the rest and not included in the deployable loadout.

The screened ammo stays with the kit for at least 6 months and then is rotated out during practice/training and replaced with newly screened ammo.

*We have seen and/or heard of 243 Win and 7-08 rounds being found in boxes of .308.

Because it is so important, I literally have this POI in every class regardless of what level instruction the class is destined for.
Click to expand...

That's great advice, I'd never thought about doing that before, but it makes a lot of sense in the bolt guns you might one day trust your life or the lives of those you care about to.
 
  • Like
Reactions: FJS, MarinePMI and Terry Cross
#16
TheJeanyus said:
Years ago I bought a case of UMC 223 ammo. One of the boxes contained 20 rounds of 7.62x39 crammed into the 223 sized holes in the plastic insert inside the box.
Click to expand...
Thanks for sharing that.
I'm only exposed to 0.0000001 percent of the shooting/training that is likely going on out there so if we are seeing it enough to be noticeable, it must be fairly common within the shooting community.
 
  • Like
Reactions: FJS
#17
I've experienced this while reloading with ELDMs, both 140 and 147 gr, 6.5CR. I seated bullets on a Zero press with a Redding competition micrometer die. I measured a random sample of rounds and found that the measure differed by as much as 0.012. I wound up re-seating, measuring each one for consistency. What a PITA. Maybe it was a lot difference. I had multiple boxes of 100 that I acquired over time. Unfortunately I had already discarded the boxes so I could not verify. I get no variance when I use Berger LRHT 144s (<0.0015" difference between rounds).

Maybe the vendors rounds are suffering from their own inconsistent bullets? Although, that wouldn't explain upside down primers or wrong ammo in boxes. :whistle:
 
#18
TBK said:
Maybe the vendors rounds are suffering from their own inconsistent bullets?
Click to expand...
I'm sure that is a thing but it is a totally different issue from what we are concentrated on in this thread.

Most/All factory SAAMI chambers are going to have enough leade length that the shooter will never see a conflict between the ogive and the actual throat when using factory ammo. SAAMI leade lengths are long enough that even inconsistent bullets with longer bearing surface/shorter ogive still have to jump at least a little bit before engaging the throat.

My above warning was regarding oversize cases.
 
  • Like
Reactions: Baron23
#19
Terry Cross said:
Yes. In fact mostly "match" and L.E. SKUs. But again, that is mostly what I'm in contact with so I can't speak for the other hunting/sporting variants.
Click to expand...
The term “Match Grade” seems to be a made up marketing term in the shooting industry. When it comes to Hornady, my experience has been that it’s laughable.

Almost as laughable as Vihtavuori putting “temperature stable” on their N560 cans. That’s a knee slapper……
 
  • Like
Reactions: flogxal, Wormydog1724, Terry Cross and 1 other person
#20
Fig said:
What's the fix? Check every round with a headspace gage? With the guys you train that may be the only prudent option. Not the same when you are shooting "work guns" that have to work every time.
Click to expand...
Dont buy cheap/shitty ammo.

Norma, Berger, Lapua ect. Hell the Norma is cheaper than anything else and shoots better than anything short of the semi custom ammo. I should stop beating the drum, before prices go up. Im off to order 2k more of Norma 6.5cm.
 
#22
OREGUN said:
This seems like a great way to have a student shoot your classroom wall but you do you.
Click to expand...
Who said anything about a classroom? I have had barrels i needed to cycle every round through to ensure feeding before a match. If you cant be trusted with a loaded gun then you should rethink your career/hobbies.

Trying to chamber a round when you NEED it and it not chambering is something that CANNOT happen.
 
  • Like
Reactions: XP1K
#23
Terry Cross said:
My soap box preaching about the shooter being the last line in the QC process is due to seeing so much of this.

I highly recommend that every shooter does goes through an ammo checklist for each and every round they have bagged to deploy with. Most are only 20 to 40 rounds.

Visually inspect each round.
Check for split necks
Check for primer / primer orientation
Check headstamp to confirm it is what was supposed to be in the box.*
Check edge of the neck to confirm it is free of shaved jacket material.

Cycle every round through the rifle that it is to deploy with. If the bolt hesitates to go down or exhibits signs of a "snug" fit, that round should be segregated from the rest and not included in the deployable loadout.

The screened ammo stays with the kit for at least 6 months and then is rotated out during practice/training and replaced with newly screened ammo.

*We have seen and/or heard of 243 Win and 7-08 rounds being found in boxes of .308.

Because it is so important, I literally have this POI in every class regardless of what level instruction the class is destined for.
Click to expand...
What Terry is referring to here, and what some people don't understand is that, he was especially concerned about working guns. If you lose a match, that sucks, but in an operational sense it a hirer stake. Working men & women don't have the option to buy or load their ammunition do to several legal hindrances. One being how it may act on target or if an agency/service weapon is destroyed do to operator error. I know most here know that. So buying the "best" is often times not even a considered option.

In my Ballistics class, when we went over ammunition I always and still recommend that if possible measure headspace, measure your OAL. Even though we don't load our own ammo, we can still sort the best from the rest. Use the rest as practice.

If you have access to multiple lots, carry the best, qual with the best. Use the worse for practice. One is for practice, the other is for lives and keeping you free and sane.

Last gig I was lucky and had 3 lots to try. Some smaller agencies, departments, or venues aren't as lucky. Mitigate what you can

As always Terry, good looking out
 
  • Like
Reactions: Rookie, 1911hombre, Baron23 and 3 others
#24
OREGUN said:
This seems like a great way to have a student shoot your classroom wall but you do you.
Click to expand...
1: You are a fucking idiot.

2: We don't ask anybody to do this during a class. We ask them to consider it as a routine equipment prep.
3: Classrooms are for pussies.
4: We cover our asses by recommending the obvious safety routines while doing so.
5: I certainly could have kept typing in this thread to explain every nuance of instruction that I recommended when we are teaching. But
for some idiotic reason, I thought that certain things would be obvious to most.
6: You are why we have to put warning labels on shit.

7: See #1 above.
8: See #1 above again but this time in bold.
 
Last edited:
  • Like
  • Love
  • Haha
Reactions: Rookie, Threadcutter308, supercorndogs and 13 others
#26
It would be interesting to hear from someone involved in the manufacturing of cases what their control process is for the physical properties of the case material.

It would seem that, even with very consistent tooling, that at some point, hardness, elasticity, and ductility variations in the case material might cause out of spec dimensional problems.
 
Last edited:
#27
When I suggested it, it wasnt necessarily to see when ammo is too big, more of the opposite. Making sure the specific round youre about to fire off isnt going to be stretching longitudinally a gross amount if one gets impatient and shoots it before gauges arrive.
I agree whole heartedly that its better to do it right- thats why I dont shoot factory ammo lol
 
Last edited:
  • Like
Reactions: supercorndogs and Terry Cross
#28
anon said:
It would seem that, even with very consistent tooling, that at some point, hardness and elasticity variations in the case material might cause out of spec dimensional problems.
Click to expand...
Most certainly. Surely they are at least attempting to monitor those variants and keep them within whatever set limits they assume to be workable.

But then, you take those same cases and run them through automated loading machines and then into automated packaging lines hoping that they aren't totally fucked when they make it to a shipping pallet.

I don't envy the ammo companies. Crazy markets on raw materials and crazy industry pressure to deliver product quickly and at competitive pricing.
 
Last edited:
  • Like
Reactions: Threadcutter308 and MarinePMI
#29
spife7980 said:
When I suggested it, it wasnt necessarily to see when ammo is too big, more of the opposite. Making sure the specific round youre about to fire off isnt going to be stretching longitudinally a gross amount if one gets impatient and shoots it before gauges arrive.
I agree whole heartedly that its better to do it right- thats why I dont shoot factory ammo lol
Click to expand...
For sure. I'm tracking and I for sure have used your method when chambering an obscure one-of that I wasn't fully tooled for. We have been fighting so many QC issues with ammo, your post just supplied the juice to have me start a separate thread.

Honestly, I guess this thread boils down to me bitching about ammo more than anything.
 
Last edited:
  • Like
Reactions: Threadcutter308 and spife7980
#31
Terry Cross said:
Fed GM308M, T308T, Hornady TAP, ELD-M, Sig LE is not usually considered "cheap/shitty ammo". But yes, I guess it would be expected to see more issues with cheap/shitty stuff.
Click to expand...
Whoie I understand most of those are the standard for LE work, they are not good performers compared to some of the brands I listed. Hornady and federal specifically have gone down the toilet in the last 5 years. Those issues don't show up at 50 or 100 yards but when stretched out you notice how bad the ads and lot to lot consistency has become. I grew up shooting cases of FGMM like many here so we realize there is a big difference between what we say before and currently. Or maybe our standards have gotten that much better with current equipment and knowledge. While the inconsistent ES might not matter for LE work it's just indictive of quality going down across the board in recent years. Improperly formed cases Is not surprising and lack of QC/QA is par for the course. It sucks you and your customers are stuck with running legacy ammo due to standards and TTP with open air and barrier rounds.
 
#32
anon said:
It would be interesting to hear from someone involved in the manufacturing of cases what their control process is for the physical properties of the case material.

It would seem that, even with very consistent tooling, that at some point, hardness and elasticity variations in the case material might cause out of spec dimensional problems.
Click to expand...
Not if you have good controls and anneal as part of the process....like premium brands do ( lapua, alpha, Peterson, ect).

Sometimes it's just simple tolerance stacking. Chamber cut on one end of tolerance and ammo made right up against that. Add in dirty chamber, dust and water and you get into issues.
 
#33
DeathBeforeDismount said:
Not if you have good controls and anneal as part of the process....like premium brands do ( lapua, alpha, Peterson, ect).

Sometimes it's just simple tolerance stacking. Chamber cut on one end of tolerance and ammo made right up against that. Add in dirty chamber, dust and water and you get into issues.
Click to expand...
Damn I bet you eat the finest caviar off a mother of pearl spoon for every meal
 
  • Haha
  • Like
Reactions: Threadcutter308 and TheBigCountry
#37
Terry Cross said:
When proper Headspace gauges are not available, this is a pretty widely used method of spitballing a sorta-close headspace. It has been used for a long time and is considered a rough cheat code to make sure the HS is in the right zip code.

My concern recently is that we have been seeing ammo quality (consistency specifically ) being all over the place. Seemingly in the last 20yrs it has gotten worse instead of better. Maybe because of 2 or 3 back to back ME wars and the producers not taking time to PM their machines and double check QC processes as much. (?)

Anyway . . . . . . . my point is that I have a literal pile of factory ammo that won't go into correctly headspaced factory chambers.

The worst offender is Hornady but I have a few Federal, Win and even Sig.
These rounds look perfect visually but are too long on the shoulder datum -> headstamp dimension. We have also seen a few that are too short on the opposite of that dimensional spectrum to the point they are inducing ignition problems.

I don't think using such a round with tape on the rear to "set" or check headspace would be "dangerous" but if the sample cartridge was out of spec, it could cause excessive brass stretch.
It could even cause the phone to ring at shops like Wade's to bitch about an out of spec chamber that is actually in spec.

@spife7980 I'm not arguing or trying to bust your chops. Just sharing my personal thoughts based on personal concerns and experience, neither of which proves I'm right. So this post is simply meant as food for thought and a "rumble strip" warning to proceed cautiously for the novices.
Click to expand...
It's gotten worse indeed. Just the weekend before last I watched a government shooter come up and ask for a cleaning rod, because the government supplied ammo he was shooting had a squib load that left a bullet in the barrel.

The companies are just running the machines too fast....
 
  • Like
Reactions: Threadcutter308, DeathBeforeDismount, Holliday and 1 other person
#39
DeathBeforeDismount said:
Dont buy cheap/shitty ammo.

Norma, Berger, Lapua ect. Hell the Norma is cheaper than anything else and shoots better than anything short of the semi custom ammo. I should stop beating the drum, before prices go up. Im off to order 2k more of Norma 6.5cm.
Click to expand...
Even that isn't a guarantee unfortunately. We had a guy send back a rifle for warranty fix due to "headspace being too short." Got it back, checked it, it was perfect. Cycled a bunch of different factory 6.5 creed through it, no problem. He sent us his ammo, Norma, every round was .004 over min headspace and would not let you close the bolt at all. Not saying Norma is shit or anything like that, but even the best brands can (and do) let things that shouldn't have passed QC get out occasionally
 
  • Like
  • Love
Reactions: Terry Cross, MarinePMI and TheBigCountry
#40
Mitten said:
Even that isn't a guarantee unfortunately. We had a guy send back a rifle for warranty fix due to "headspace being too short." Got it back, checked it, it was perfect. Cycled a bunch of different factory 6.5 creed through it, no problem. He sent us his ammo, Norma, every round was .004 over min headspace and would not let you close the bolt at all. Not saying Norma is shit or anything like that, but even the best brands can (and do) let things that shouldn't have passed QC get out occasionally
Click to expand...
Yep, every company has a few "oh, shit"'s. I had a lot of Lapua 6mm CM not too long ago that must have either bypassed the final annealing process, or someone pulled them from the annealing oven too soon. They were hard as all get out. Nothing I couldn't resolve myself, but as Terry said above, "The shooter is the final person in the QC process".

Words worth remembering for many...
 
  • Like
Reactions: 6.5SH, Threadcutter308, Mitten and 1 other person
#41
roostercogburn98 said:
You truly are a southern gentleman
Click to expand...
Hmmmm..... True southern gentlemen don't call other forum members "a fucking idiot".

.
.

.
.
.
.

A true southern gentleman would have said, "You are a fucking idiot., bless your little heart."
 
  • Haha
  • Love
Reactions: Threadcutter308, drglock, B'N'F and 7 others
#43
Terry Cross said:
1: You are a fucking idiot.

2: We don't ask anybody to do this during a class. We ask them to consider it as a routine equipment prep.
3: Classrooms are for pussies.
4: We cover our asses by recommending the obvious safety routines while doing so.
5: I certainly could have kept typing in this thread to explain every nuance of instruction that I recommended when we are teaching. But
for some idiotic reason, I thought that certain things would be obvious to most.
6: You are why we have to put warning labels on shit.

7: See #1 above.
8: See #1 above again but this time in bold.
Click to expand...
Allow me to reiterate: You said you were instructing your tactard students to cycle every round through their chamber. I don’t want to be anywhere near whatever facility it is you’re using when you instruct a group of lowest-common-denominators to cycle all of their ammunition through whatever lowest-bidder-supplied gun they’re using.

Now you and dildobeforedismount go back to whatever southern dandy mutual ball swallowing you were doing you useless motherfucker. Fuck your little heart upside down.
 
  • Haha
  • Wow
Reactions: 1911hombre, mtrmn, Rubicon Precision and 3 others
#44
OREGUN said:
Allow me to reiterate: You said you were instructing your tactard students to cycle every round through their chamber. I don’t want to be anywhere near whatever facility it is you’re using when you instruct a group of lowest-common-denominators to cycle all of their ammunition through whatever lowest-bidder-supplied gun they’re using.

Now you and dildobeforedismount go back to whatever southern dandy mutual ball swallowing you were doing you useless motherfucker. Fuck your little heart upside down.
Click to expand...
You’re a spicy meatball ain’t ya
 
  • Haha
  • Like
Reactions: Threadcutter308, supercorndogs, 1911hombre and 4 others
#46
I just had an older box of Hornady 22-250 50gr Superperformance that had at least six give me a hard bolt lift in my AIAT. Like, hard enough for me to have to slap the handle up fairly hard.

Then about five additional rounds gave me a stiff-ish bolt lift. Three rounds were fine.

The remaining six unfired rounds were dumped into the range’s “dud” box. Not taking any more chances on that box.

That box of ammo was roughly from the Covid time. Other, newer boxes of the same stuff were fine, but some older boxers were ok too.

Beats me.
 
  • Like
Reactions: Terry Cross
#49
carbonbased said:
Pretty soon we’ll all learn that cellophane tape manufacturers have had wildly different thicknesses over lots.

View attachment 8737900
Click to expand...
Well if you only buy American made Scotch tape you can ensure your tape thickness will be within .0005 thou variance. Buy that chicom shit, its your funeral bub.
 
  • Haha
Reactions: supercorndogs and carbonbased
You must log in or register to reply here.

Similar threads

memilanuk
6 ARC headspace
Replies
15
Views
896
flogxal
flogxal
SuperToaster
Zermatt Orgin 6.5CM light primer strikes??? ( pic heavy) *RESOLVED*
Replies
16
Views
1K
SuperToaster
SuperToaster
P
Sizing Dies and Barrel Change
Replies
9
Views
458
918v
918v
M
Gunsmithing Headspace question after barrel move
Replies
5
Views
593
fdkay
F
T
I'm sorry, another over-pressure post....
Replies
36
Views
2K
Thorspapa
T
Top Bottom
Back
Home
Forums
Merch
Alerts